Renal manifestations of sarcoidosis

Renal manifestations of sarcoidosis are rare. In addition to calcium nephropathy, granulomatous interstitial nephritis and glomerulo-nephritis (GN) account for most cases. The latter two manifestations are described in 4 patients and in a detailed review of the literature. In comparison to a nonselected population of sarcoidosis patients, granulomatous interstitial nephritis is found more frequently in male patients above 40 years of age; it is associated more frequently with other extrathoracic manifestations of sarcoidosis; and it causes renal insufficiency of varying degree, which is at least partially reversible with steroid therapy. Predominant findings are silent microhematuria, sterile pyuria, mild proteinuria and a variety of tubular functional disorders. Glomerulonephritis (39 observations) has been described with increasing frequency in sarcoidosis. Because of the well known immunological abnormalities of sarcoidosis, frequent association of sarcoidosis with GN could be expected but this association has not yet been proven statistically. Sarcoidosis-associated GN includes a variety of histological forms, viz. membranous, proliferative and sclerosing GN. Glomerulonephritis may appear before sarcoidosis. Conversely, both diseases may appear simultaneously, or GN may follow all other manifestations of sarcoidosis with a latency period of many years.